Magnetic tape recording/reproducing device comprising a head-drum unit using capacitive and inductive couplings to transfer signals from and to the write and read heads

Abstract

A magnetic-tape recording/reproducing device of the helical-scan type includes a head drum unit having first and second signal transmission systems arranged between the stationary part and a rotary magnetic head. The first transmission system transmits signals by an inductive coupling. The second transmission system transmits signals by a capacitive coupling.

What is claimed is: 
     
       1. A head-drum unit for use in a magnetic-tape recording/reproducing device, the head-drum unit having a rotatable supporting member and a stationary part, characterized in that the head-drum unit comprises first and second means for signal transmission between the stationary part and a magnetic head arranged on the supporting member, the first means for signal transmission transmitting signals by means of a substantially inductive coupling, and the second means for signal transmission transmitting signals by means of a substantially capacitive coupling. 
     
     
       2. A magnetic-tape recording/reproducing device of the helical-scan type, comprising a head-drum unit having a rotatable supporting member and a stationary part, characterized in that the head-drum unit comprises first and second means for signal transmission between the stationary part and a magnetic head arranged on the supporting member, the first means for signal transmission transmitting signals by a substantially inductive coupling, and the second means for signal transmission transmitting signals by a substantially capacitive coupling. 
     
     
       3. A magnetic-tape recording/reproducing device as claimed in claim 2, wherein the rotatable supporting member has a first and a second wall surface, and the stationary part of the head-drum unit has a third and a fourth wall surface, characterized in that the first means for signal transmission comprises a rotor winding arranged on the first wall surface and a stator winding arranged on the third wall surface such that the rotor winding faces the stator winding with which it cooperates, and the second means for signal transmission comprises a rotor capacitor plate arranged on the second wall surface and a stator capacitor plate arranged on the fourth wall surface such that the rotor capacitor plate faces the stator capacitor plate with which it cooperates. 
     
     
       4. A magnetic-tape recording/reproducing device as claimed in claim 1, characterized in that the rotatable supporting member carries at least a first and a second magnetic head, the first magnetic head being coupled to the first means for signal transmission, and the second magnetic head being coupled to the second means for signal transmission, wherein one of the first and second magnetic heads is a read head and the other of the first and second magnetic heads is a write head. 
     
     
       5. A magnetic-tape recording/reproducing device as claimed in claim 4, wherein the rotatable supporting member has a first and a second wall surface, and the stationary part of the head-drum unit has a third and a fourth wall surface, characterized in that the first means for signal transmission comprises a rotor winding arranged on the first wall surface and a stator winding arranged on the third wall surface such that the rotor winding faces the stator winding with which it cooperates, and the second means for signal transmission comprises a rotor capacitor plate arranged on the second wall surface and a stator capacitor plate arranged on the fourth wall surface such that the rotor capacitor plate faces the stator capacitor plate with which it cooperates. 
     
     
       6. A magnetic-tape recording/reproducing device as claimed in claim 4, characterized in that the first magnetic head is the write head, and the second magnetic head is the read head. 
     
     
       7. A magnetic-tape recording/reproducing device as claimed in claim 6, wherein the rotatable supporting member has a first and a second wall surface, and the stationary part of the head-drum unit has a third and a fourth wall surface, characterized in that the first means for signal transmission comprises a rotor winding arranged on the first wall surface and a stator winding arranged on the third wall surface such that the rotor winding faces the stator winding with which it cooperates, and the second means for signal transmission comprises a rotor capacitor plate arranged on the second wall surface and a stator capacitor plate arranged on the fourth wall surface such that the rotor capacitor plate faces the stator capacitor plate with which it cooperates. 
     
     
       8. A magnetic-tape recording/reproducing device as claimed in claim 7, characterized in that the head-drum unit comprises a rotor core and a stator core of a ferromagnetic material, the rotor core serving as a support for the rotor winding and the stator core serving as a support for the stator winding, the rotor core further serving as a support for the rotor capacitor plate and/or the stator core further serving as a support for the stator capacitor plate. 
     
     
       9. A magnetic-tape recording/reproducing device as claimed in claim 7, characterized in that imaginary surfaces in which the first and the second wall surfaces lie, substantially coincide, and/or imaginary surfaces in which the third and the fourth wall surfaces lie, substantially coincide. 
     
     
       10. A magnetic-tape recording/reproducing device as claimed in claim 9, characterized in that the head-drum unit comprises a rotor core and a stator core of a ferromagnetic material, the rotor core serving as a support for the rotor winding and the stator core serving as a support for the stator winding, the rotor core further serving as a support for the rotor capacitor plate and/or the stator core further serving as a support for the stator capacitor plate. 
     
     
       11. A magnetic-tape recording/reproducing device as claimed in claim 7, characterized in that the first and the third wall surfaces lie in substantially concentric cylindrical imaginary surfaces, and/or the second and the fourth wall surfaces lie in substantially concentric cylindrical imaginary surfaces. 
     
     
       12. A magnetic-tape recording/reproducing device as claimed in claim 1, characterized in that the head-drum unit comprises a rotor core and a stator core of a ferromagnetic material, the rotor core serving as a support for the rotor winding and the stator core serving as a support for the stator winding, the rotor core further serving as a support for the rotor capacitor plate and/or the stator core further serving as a support for the stator capacitor plate. 
     
     
       13. A magnetic-tape recording/reproducing device as claimed in claim 11, characterized in that the imaginary surfaces in which the first and the second wall surfaces lie, substantially coincide, and/or the imaginary surfaces in which the third and the fourth wall surfaces lie, substantially coincide. 
     
     
       14. A magnetic-tape recording/reproducing device as claimed in claim 13, characterized in that the head-drum unit comprises a rotor core and a stator core of a ferromagnetic material, the rotor core serving as a support for the rotor winding and the stator core serving as a support for the stator winding, the rotor core further serving as a support for the rotor capacitor plate and/or the stator core further serving as a support for the stator capacitor plate. 
     
     
       15. A magnetic-tape recording/reproducing device as claimed in claim 7, characterized in that the first and the third wall surfaces lie in substantially parallel imaginary surfaces perpendicular to the direction of rotation of the rotatable supporting member, and/or the second and the fourth wall surfaces lie in substantially parallel imaginary surfaces perpendicular to the direction of rotation of the rotatable supporting member. 
     
     
       16. A magnetic-tape recording/reproducing device as claimed in claim 15, characterized in that the head-drum unit comprises a rotor core and a stator core of a ferromagnetic material, the rotor core serving as a support for the rotor winding and the stator core serving as a support for the stator winding, the rotor core further serving as a support for the rotor capacitor plate and/or the stator core further serving as a support for the stator capacitor plate. 
     
     
       17. A magnetic-tape recording/reproducing device as claimed in claim 15, characterized in that the imaginary surfaces in which the first and the second wall surfaces lie, substantially coincide, and/or the imaginary surfaces in which the third and the fourth wall surfaces lies substantially coincide. 
     
     
       18. A magnetic-tape recording/reproducing device as claimed in claim 17, characterized in that the head-drum unit comprises a rotor core and a stator core of a ferromagnetic material, the rotor core serving as a support for the rotor winding and the stator core serving as a support for the stator winding, the rotor core further serving as a support for the rotor capacitor plate and/or the stator core further serving as a support for the stator capacitor plate. 
     
     
       19. A magnetic-tape recording/reproducing device as claimed in claim 18, characterized in that at least a part of the rotor core and/or the stator core is made of a substantially non-conductive ferromagnetic material, and the rotor capacitor plate and/or the stator capacitor plate is made of a conductive material applied, at least partly, to the substantially non-conductive ferromagnetic material. 
     
     
       20. A magnetic-tape recording/reproducing device as claimed in claim 19, characterized in that the first means for signal transmission comprises at least two rotor windings and two stator windings, a rotor capacitor plate being interposed between the rotor windings, and a stator capacitor plate being interposed between the stator windings.